Starter jaw mechanism



Dec. 17, 1957 H. TROEGER STARTER JAW MECHANISM 2 Sheets-Sheet 1 Filed April 16, 1953 R m m m HQ 1 v \\V 5 M E 5% w 0 HE. D w- O- E g n 6E 197 OKA/E Dec. 17, 1957 H. TROEGER $816,449

STARTER JAW MECHANISM Filed April 16, 1953 2 Sheets-Sheet 2 FIG. 2

INVENTOR.

HENRY TROEGER United States Patent STARTER JAW MECHANISM Henry Troeger, Ramsey, N. J., assignor to Bendix Aviation Corporation, Teterboro, N. J., a corporation of Delaware Application April 16, 1953, Serial No. 349,211

6 Claims. (Cl. 747) The present invention relates to engine starters and more particularly to an overload release mechanism adapted for starting jet engines.

It is necessary that starters for turbine engines operate at a high speed in order to bring the engine up to a selfsustaining speed. Various types of starters such as those of the turbine type which are suitable for the high speed operation have a very high rate of acceleration and it is desirable that the starter be connected to the engine before energizing the starter. With the conventional screw shaft type starter jaws, before meshing would occur the jaw would be up to a substantially high speed causing severe shock on meshing. It has been found that an overrunning or one-way clutch is satisfactory to connect the starter to the engine.

ln operation upon the starter being energized, torque is transmitted through the overrunning clutch to the engine member. Upon the engine obtaining speed greater than that of the starter the clutch permits the engine to overrun the starter thereby disconnecting it from the engine.

In certain instances however, the overruning clutch has been known to seize and not release to permit the engine to overrun the starter. The present invention provides novel means whereby the high torque output of the starter may be satisfactorily transmitted in one direction to the engine and it will disconnect the starter from the engine should some small predetermined torque be applied in the other direction. In the present invention the jaws on the output shaft are held in driving connection with those of a spline jaw block which is held in place by a latch device which comprises a multifingered plate attached to the output shaft and which engages a cylindrical sleeve attached to the driving shaft.

it is an object of the invention to provide a novel reverse overload release mechanism.

Another object of the invention is to provide a novel jaw mechanism for a starter.

Another object of the invention is to provide an emergency release mechanism.

The above and other objects and features of the invention will appear more fully hereinafter from a consideration of the following description taken in connection with the accompanying drawings wherein one embodiment of the invention is illustrated by way of example.

in the drawings:

Figure 1 is a partial cut-away view of a starter embodying the invention.

Figure 2 is an end view illustrating the fingered plate.

Figure 3 is a cross sectional view of the cylindrical sleeve for engaging the fingered plate.

Referring now to the drawing, a starter is indicated generally by the numeral 1 and has a housing 2 adapted to be secured to an engine mounting flange 3 by a quick disconnect coupling 4. The quick disconnect coupling 4 may be of the type disclosed and claimed in Patent No. 2,553,220 issued May 15, 1951, to Henry Trocger. A drive plate 5 is connected through overrunning clutch 6 to gearing 7 which is driven from a suitable source of motive power such as a gas turbine or the like. The plate 5 is mounted on bearings 8 supported by an extension 9 of the gearing 7.

The plate 5 has its external splines 10 adapted to slidingly engage a spline jaw block 11 which has internal splines 12 and a starter jaw tooth set 13 on one end thereof. The teeth 13 normally engage a mating set of starter jaw teeth 14 on an output shaft 15 adapted to be splined for engagement with a main engine (not shown).

A cylindrical like sleeve 16 holds the spline jaw block 11 in engagement with the splines 10 on the drive plate 5. A pin 17 fitted in the block 11 is adapted to engage a slot 18 in the sleeve 16 to hold the sleeve 16 in proper alignment. The sleeve 16 has a plurality of counterbore portions 19 adapted to receive a plurality of springs 20 which serve to bias the spline block 11 into engagement with the member 15. Also positioned between a flange 21 on the sleeve 16 and shoulder 22 on the member 5 is a pull back spring 23.

The sleeve 16 has a plurality of slots 24 which may best be see in Figure 3. The slots 24 are adapted to cooperate with fingers 25 on a latch plate 26 secured to the output member 15 by rivets 27. The slots 24 are so designed that torque may be transmitted in one direction only and that a reverse torque will move the fingers 25 out of the slots 24.

In operation when the engine has started and has at tained a self-sustaining operating speed, the overrunning clutch prevents the engine from driving the starter turbine at excessively high speed, however, in the case of malfunction of the clutch 6, the spring 20 will permit the teeth 13 and 14 to ratchet, thus placing the load upon the fingers 25. Inasmuch as the fingers 25, in the reverse direction, merely drive the ring 16 through friction, upon the torque exceeding a predetermined amount, the friction will be overcome and the fingers 25 will be moved out of engagement with the slots 24. This relieves the tension upon the spring 20 and enables the spring 23 to move the spline block 11 out of engagement with the output member 15. The rivets 27 holding the plate 26 to the member 15 are provided with a large head and serve as bearings for the output member 15 upon the jaws being released.

Although only one embodiment of the invention has been illustrated various changes in the form and relative arrangement of the parts, which will now appear to those skilled in the art may be made without departing from the scope of the invention.

What is claimed is:

1. For use in an engine starter of the type having a starter jaw connected to an engine member by an overrunning clutch, the combination comprising a first member connected for rotation in one direction by said overrunning clutch, a second member adapted to be connected to said engine member, spline means for interconnecting said members, spring means for normal biasing said spline means into engagement, and friction means responsive to a predetermined torque by said second member to release said spring means thereby to move said spline means out of engagement.

2. For use in an engine starter, the combination c0mprising a drive plate, output gearing, an overrunning clutch connecting said drive plate with said output gearing for transmitting torque in one direction, a splined jaw block carried by said drive plate and movable axially relative thereto, an engine jaw member adapted to mate with said jaw block, spring means normally biasing said jaw block into engagement with said engine jaw, other spring means for biasing said jaw block out of engagement with said engine jaw, and latching means for normally preventing said other'spring means from disengaging said jaw block and said engine jaw, said latching means being responsive to a predetermined reversetorque'to permit said other spring means to disengage said jaw block from said engine jaw.

3. A reverse torque disconnect mechanism comprising a driving: member, ;a driven member asplined'jaw -member carried by'said driving member and movable .axially relative thereto, said driven member having a mating jaw portion, ,yieldablemeans for normally biasing said jaws together, spring means for urging-said jaws out of engagement, restraining means for normally preventing said spring means from urging said jaws out of engagement, and means responsive to torque in a reverse direction exceeding a predeterminedvalue to release said restraining means.

4. A reverse torque disconnecting mechanism for use in an engine starter connected to an engine member by an overrunning clutch, comprising a driven member adapted to be rotated in a predetermined direction through said overrunning:clutch,;a driven member adapted for connection to an engine member and having starter jaw teeth thereon, a splined jaw block carried by said driven member and movable axially relative thereto, said jaw block having mating starter jaw teeth thereon, retaining means including a spring for normally urging said teeth into engagement, latching means carried by said driven member for holding said retaining means in an operative position, said latching means being responsive to reverse torque to release said retaining means, and means for urging said jaws out of engagement upon the release of said retaining means.

5. A reverse torque disconnect mechanism for use in an engine starter connected to drive an engine member through an overrunning clutch, comprising a driving member connected for rotation through said overrunning clutch, a driven member yieldabIe jaw tooth means for interconnecting said driving and driven members, and means responsive to a predetermined value of reverse torque which results when said driven member attains a speed greater than said driving member and said clutch does not release for disconnecting said jaw tooth means.

6. A reverse torque disconnect mechanism for use with an engine starter connected to an engine by an overrunning clutch, comprising a driving member, a splined jaw block rotatable with and movable axially relative to said driving member, an axially stationary rotatable driven member having jaws adapted to mate with said jaw block, a retaining ring connected for rotation with and axial movement relative to said jaw block, spring means adapted to be compressed between a flange on said retaining ring and said jaw block. for yieldably urging said jaw block into engagement with said output member, a fingered plate secured to said output members and-adapted to coact with slots in said ring-member'to hold said ring member in a position to place tension on said spring means, said fingered member being responsive to reverse torque to move out of engagement with said slots, and other spring means for urging said jaw block out of engagement with said output member upon said fingered member being moved out of engagement with said slots.

Metsger Jan. 20, 1953 Miller July 7, 1953 

